I really like the Josephus Problem ([Numberphile‘s Video on YT](https://youtu.be/uCsD3ZGzMgE https://youtu.be/uCsD3ZGzMgE)) because of the binary twist, really

I really like the Josephus Problem ([Numberphile‘s Video on YT](https://youtu.be/uCsD3ZGzMgE https://youtu.be/uCsD3ZGzMgE)) because of the binary twist, really enjoyed Veritasium‘s [3x+1](https://youtu.be/094y1Z2wpJg https://youtu.be/094y1Z2wpJg) and my favorite is your described [100 Prisoners Riddle](https://youtu.be/iSNsgj1OCLA https://youtu.be/iSNsgj1OCLA) too